An unnamed ministry official later said Kim Yong Jin was put before a firing squad last month after he was accused of exhibiting a "bad attitude" while attending a June parliamentary session. He was condemned for committing "anti-party, anti-revolutionary" acts.

Meanwhile, one of the two senior figures who were sent to re-education camps was 71-year-old Kim Yong Chol, believed to have planned the sinking of a South Korean warship in 2010.

If confirmed, Kim Yong Jin's death would be the latest in a wave of punishments, including executions, ordered by Kim Jong Un since he took power in 2011.

In February, Seoul said the North's military chief of staff had been executed, but he later resurfaced at a party rally in May.